Is Russia playing both sides on Iran nukes?

Russia signals that it is open to tougher sanctions on Iran, which has failed to respond to an international uranium deal. But rogue scientists in Russia may be continuing to help Iran pursue a nuclear program.

Russia's President Dmitry Medvedev speaks with German journalists Sunday at the Gorki residence outside Moscow. Sanctions against Iran should not be ruled out if it fails to agree to restrictions on its nuclear program, Medvedev told the German weekly magazine Der Spiegel.

Washington — Iran's failure to respond to an international offer to enrich much of its uranium stockpile outside the country – for use in a Tehran medical research facility – is again raising the prospect of tougher sanctions.

Much of the focus of the sanctions debate is falling on Russia, which has blown hot and cold on additional punitive measures on Iran over its nuclear program – but which is sounding open to the idea once again. The attention is reviving lingering questions about Russian assistance – either official or unauthorized – to Iran's nuclear program and weapons research.

Russian President Dmitry Medvedev and French President Nicolas Sarkozy issued a statement Monday warning Iran that "the international community's patience is not infinite." The two leaders, in Berlin for the 20th anniversary of the fall of the Berlin Wall, said they "do not rule out" another round of sanctions aimed at the Iranian leadership and its advancing nuclear program.

Those words followed comments by President Medvedev over the weekend to German journalists, when he suggested that Russia could support additional sanctions if Iran fails to take the opportunity to cooperate with world powers in its nuclear program. Noting the offers now before the Iranian leadership, Medvedev told Germany's Der Spiegel magazine, "I wouldn't like to see all that ending in the introduction of international sanctions … but if there is no movement forward, no one is excluding such a scenario."

The US, Russia, and France last month negotiated a deal with Iranian officials to remove almost three-quarters of Iran's slightly-enriched uranium stockpile to Russia and France for further enrichment to a level needed for a research reactor. Removal of the uranium would ease international concerns about Iran's nuclear intentions and allow for what the Obama administration hopes would be fruitful negotiations with Iran on a range of issues.

But Iranian state media reports and statements from some Iranian lawmakers suggest the government will reject the deal – perhaps offering to buy the uranium it needs for its reactor and moving its uranium stockpile to a domestic location for international surveillance instead.

Eyes have turned to Russia because, as a veto-wielding member of the UN Security Council, it could squelch any move to impose additional sanctions through the council. China also holds veto power in the Security Council and has discouraged talk of a new sanctions resolution, but some diplomats believe that it would go along if Russia decided to support new punitive measures.

Russia also has close economic ties to Iran and a history of cooperation with Iran on both its nuclear program and defensive military development.

Officially, Russia has sold defensive missile systems to Tehran – though it is currently holding up delivery of a more sophisticated surface-to-air system, drawing protests from Iranian officials. "The Russians seem to modulate that cooperation depending on how things are going," Mr. Albright says, noting there could be a connection between Iran's lack of response to the uranium deal and the Russian brakes on delivery of the new missile system.

But suspicions have also grown over the last year that Russian scientists, perhaps acting in an unofficial or "rogue" capacity, have been assisting their Iranian colleagues in pursuit of a nuclear weapon and weapons delivery systems. Israeli Prime Minister Benjamin Netanyahu is believed to have flown secretly to Moscow in September to present Medvedev and Russian Prime Minister Vladimir Putin with a list of names of Russian scientists that Israel says took nuclear know-how to Iran.

Those reports have prompted some members of Congress to pressure President Obama to report to Congress on suspected Russia-Iran nuclear cooperation before the US pursues any new or additional nuclear accords with Russia.